Turbomachine blade lock and seal device

ABSTRACT

This invention comprises a combined structure for locking blades to the rotor disk of a turbomachine and for preventing fluid from leaking between the rotor disk and an inner shroud ring of adjacent stationary vanes during turbomachine operation.

United States Patent 1191 Amos [ Oct. 15, 1974' [5 TURBOMACHINE BLADE LOCK AND SEAL 1/1967 Hall, Jr. 416/221 DEVICE 3,455,537 7/1969 Kozlin et a1... 415/134 3,656,864 4/1972 Wagle 416/221 Inventor: David J. Amos, Walhngford, Pa. 3,761,200 9/1973 Gardiner 415/172 [73] Assignee: Westinghouse Electric Corporation,

plttsburgh Primary ExaminerHenry F. Raduazo [22] Filed: Mar. 9, 1973 Attorney, Agent, or Firm-D. N. Halgren [21] Appl. No.: 339,700

I [57] ABSTRACT [52] US. Cl. 415/172, 416/220 [51] Int. Cl. Fold 5/20 This invention comprises a combined structure for [58] held of Search 415/169 171, locking blades to the rotor disk of a turbomachine and 415/173 113;1'16/119220 221 for preventing fluid from leaking between the rotor disk and an inner shroud ring of adjacent stationary [56] References C'ted vanes during turbomachine operation.

UNITED STATES PATENTS 3,023,998 3/1962 Sanderson, Jr. 416/220 I 6 Claims, 7 Drawing Figures ""Ilm PATENTEUucnsrsm v w I saw 20E 3 PATENTEDUBT 5 M sum 3 or '3 FIG].

TURBOMACl-IINE BLADE LOCK AND SEAL DEVICE BACKGROUND OF THE INVENTION The present invention relates to turbomachin'es and particularly to a combined structure for locking rotor blades to the disc and sealing fluid in the fluid flowpath.

Blade locking devices have heretofore been separate and distinct from the sealing devices on turbomachines. Blade locks are often some type of clip or bolt-on device, and seals are often bolted to portions of the disc near the blade lock. Arrangements such as these are undesirable in that bolt holes must be machined in the rotor disc taking valuable manufacturing time and money, while creating potentially hazardous situations due to high stress concentrations and unbalance near the bolt holes in the vicinity of the periphery of the rotor disc. Some sealing methods make use of the rotor land, or platform, but in the present invention, these are obviated. requiring a thinner rotor casting, less material and less machining, to reach the operational size of the rotor disc. t

SUMMARY OF THE INVENTION In accordance with one embodiment of the invention a locking and sealing member is associated with each blade on a turbomachine rotor disc. The lock and seal device has one member which is'disposed in the groove beneath the blade root on the rotor periphery. It locks the blade in place with respect to the disc, the seal members extend beyond both sides of the disc and form a fluid seal with shrouds that are attached to the radially inner ends of stationary vanes circumferentially disposed about both sides of the rotor disc.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the nature of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a partial longitudinal sectional view of a turbomachine showing a locking and sealing device constructed in accordance with this invention;

FIG. 2 is a fragmentary perspective view showing an H" shaped member of the lock and seal device;

FIG. 3 is a plan view of an alternative embodiment of the H" shaped member;

FIG. 4 is an elevational view of the IV-shaped member shown in FIG. 3;

FIG. 5 is a perspective view of a turbomachine blade used in this invention;

FIG. 6 is a fragmentary sectional view showingthe lock and seal device assembled, and a fragmentary sectional view of an assembly-disassembly tool;'

FIG. 7 is a sectional view of an alternative embodiment of the sealing device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, particularly to FIG. I, the structure shown therein comprises a portion of an axial flow turbomachine 10 which includes a rotor disc 12, a series of generally axially disposed grooves I4 on the periphery of disc 12, a blade lock and seal device 16 longitudinally disposed in each groove 14, a series of I ally directed plurality of stationary vanes 20 circumferentially disposed both upstream and downstream of the rotor disc 12, supported on their radially outer ends by a turbomachine casing 22, and on their inner ends by a shroud 24.

The blade lock and seal device 16 includes an H"- shaped member 26 as shown in FIG. 2, having a bridge member 27, a hole 28 in the bridge member 27, a pair of parallel trough-shaped members 30, each having a flange member 32 that forms a seal with the stationary shrouds 24 on both sides of the disc 12, and a pin 34 attached to a bias producing spring member 36 the latter two being shown in FIG. 1.

An alternative embodiment of the H-sh aped member 26 is shown in FIGS. 3 and 4 wherein member 26 has trough segments 29 and 31 of unequal length. This offset in length induces a twisting moment, M, during disc rotation. This creates an improved seal between adjacent trough members. Shown in FIG. 4 is an overlap arrangement where the abutting inclined surfaces 38 and 38' of adjacent troughs overlap. The inclined contiguous surfaces 38 and 38 can be parallel or nonparallel. The detail of FIG. 4 shows an example of a non-parallel arrangement, that is, where 0 6,. This non-parallelism in mating surfaces improves the sealing between the adjacent troughs because the surfaces will mate more closely as moment M increases.

The blade 18 as shown in FIG. 5, has a root portion 40, an axially aligned slot 42 disposed in root portion 40, and an indentation 44 located in slot 42. The slot 42 is used to facilitate ingress and egress of a blade insertion-removal tool 46, partially illustrated in FIG. 6,. The rotor disc 12 in FIG. 6 is shown with the bridge member 27 portion of the lock and seal device 16 disposed in groove 14. The trough-shaped members 30 extend beyond and overhang both ends of the groove 14 in an abutting relationship with the sides of the disc 12. Disposed in the groove 14 is bias producing spring member 36, and attached thereto is a pin member 34. The pin 34 registers through hole 28 in the bridge member 27, and is forced by the spring 36 into interlocking engagement with the indentation 44 in the blade root 40 of the turbomachine blade 18. Assembly of the arrangement includes: positioning the spring member 36 and the attached pin 34 against the radially inward surface of the groove 14; placing the lock and seal device 16 radially outward of the spring 36 so that the pin 34 registers through the hole 28 on the bridge member 27 of the lock and seal device 16; applying a pressure on the device 16 by depressing the tool 46 in the radially inward direction to compress the spring 36; sliding the blade root 40 into the groove 14 radially outward of the device 16, until the indentation 44 is aligned with the pin 34. Withd rawal of the tool 46 allows the interlocking engagement between the root 40 and the pin 34 to take place. The overhanging abutting troughs 30 prevent the device 16 from moving with respect to the disc 12. For removal of the blade 18, a reversal of the above procedure would be necessary. An alternative embodiment of the sealing means is shown in FIG. 7, wherein a plurality of parallel radially directed flanges 48 form a labyrinth sealing arrangement with the stationary shrouds 24. Methods for restraining the lock and seal device 16 from movement with respect to the disc 12 other than that due to the overhanging abutting troughs 30 on each side of the disc 12 could be accomplished by arrangements of biased pins, bolts or guides. Sealing would still occur between the shrouds 24 and extensions from the bridge member 27 beyond the side of the disc 12. Use of lock and seal devices of the type described above obviates the necessity of rotor lands or platforms as they are sometimes called. The platforms ordinarily support or are a part of the sealing portion of a rotor disc. In the present invention, we do not have the need for the platform, hence the disc could be manufactured from a thinner blank, requiring less material and less machining to final dimensions.

From the foregoing description, it is apparent that the invention provides a combined blade lock and fluid seal assembly for use with turbomachines, rotor blades and discs, wherein undesirable stress concentration in the rotor discs are reduced; fluid leakage between rotor discs and stator vanes is reduced, efficiencies of the turbomachines are increased; weight of the rotor disc forging is decreased. All of which is due to an economically produced, easily assembled and disassembled combined locking device for turbomachine rotor baldes and sealing device for turbomachine fluid flow paths.

While other modifications of this invention, and changes and substitutions of equivalence which might have been made have not been described in detail, it is desired to cover by the appended claims all such modifications as fall within the true spirit and scope of the invention.

What I claim is:

l. A turbomachine assembly having at least one rotatable disc member having a plurality of generally axially disposed grooves therein, a plurality of radial blades having root portions engaged on said grooves, an annular array of stationary radially directed vanes on each side of said disc, each of said stationary arrays of vanes including a shroud joining the radially inner ends of the vanes, and a locking and sealing member associated with each of said radialv blades, each locking and sealing member being disposed longitudinally within one of said generally axially disposed grooves between said groove and said blade root, and engaging the blade root disposed therein by a pin member biasedly registered therebetween to lock the blade'in its axial position with respect to said locking and sealing member, and each locking and sealing member having portions extending on each side of the disc adapted to secure said locking and sealing member axially in said groove and to form a seal with the adjacent shroud.

2. The combination as recited in claim 1, wherein each of said root portions of said radial blades has an axially extending slot and an indentation in said slot, said indentation receiving said biased pin member, said axially extending slot permitting disposition of said locking and sealing member therein.

3. The combination as recited in claim 1, wherein said locking and sealing member comprises a strip of material disposed throughout said groove and extending beyond both sides of said disc, said strip of material having a hole therethrough, a bias producing means, and a radially movable pin attached to said bias producing means, said pin registering through said hole and forcibly held in interlocking engagement with said indentation by said bias producing means.

4. The combination as recited in claim 3, wherein said strip of material disposed in said groove is in a locked relationship with respect to said disc.

5. The combination as recited in claim 3, wherein said bias producing means is a spring.

6. The combination as recited in claim 3, wherein said portion of material extending beyond said disc is arranged to form at least one trough-shaped segment on each side of and abutting said disc, wherein at least one outer radially directed flange of said trough forms a seal with said shroud. 

1. A turbomachine assembly having at least one rotatable disc member having a plurality of generally axially disposed grooves therein, a plurality of radial blades having root portions engaged on said grooves, an annular array of stationary radially directed vanes on each side of said disc, each of said stationary arrays of vanes including a shroud joining the radially inner ends of the vanes, and a locking and sealing member associated with each of said radial blades, each locking and sealing member being disposed longitudinally within one of said generally axially disposed grooves between said groove and said blade root, and engaging the blade root disposed therein by a pin member biasedly registered therebetween to lock the blade in its axial position with respect to said locking and sealing member, and each locking and sealing member having portions extending on each side of the disc adapted to secure said locking and sealing member axially in said groove and to form a seal with the adjacent shroud.
 2. The combination as recited in claim 1, wherein each of said root portions of said radial blades has an axially extending slot and an indentation in said slot, said indentation receiving said biased pin member, said axially extending slot permitting disposition of said locking and sealing member therein.
 3. The combination as recited in claim 1, wherein said locking and sealing member comprises a strip of material disposed throughout said groove and extending beyond both sides of said disc, said strip of material having a hole therethrough, a bias producing means, and a radially movable pin attached to said bias producing means, said pin registering through said hole and forcibly held in interlocking engagement with said indentation by said bias producing means.
 4. The combination as recited in claim 3, wherein said strip of material disposed in said groove is in a locked relationship with respect to said disc.
 5. The combination as recited in claim 3, wherein said bias producing means is a spring.
 6. The combination as recited in claim 3, wherein said portion of material extending beyond said disc is arranged to form at least one trough-shaped segment on each side of and abutting said disc, wherein at least one outer radially directed flange of said trough forms a seal with said shroud. 